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> It explained how the Earth generates the magnetic field that protects the planet from cosmic radiation, Our protection from cosmic radiation is mostly due t

by pfdietz 10mo ago

> It explained how the Earth generates the magnetic field that protects the planet from cosmic radiation, Our protection from cosmic radiation is mostly due to Earth's thick atmosphere, not its magnetic field.

nobodyandproud 10mo ago
I don’t see any problems with the quote.
nephihaha 10mo ago
The magnetic field deflects particles from the Solar Wind, whereas the atmosphere blocks a lot of the radiation as I understand it.
- pfdietz 10mo ago
  The solar wind != cosmic radiation.
deleted 10mo ago
[deleted]
Qem 10mo ago
Without magnetic fields, the solar wind strips away atmospheres, like what happened to Mars.
- pfdietz 10mo ago
  This is questionable. https://earthscience.stackexchange.com/questions/14915/does-the-magnetic-field-really-protect-earth-from-anything https://earthscience.stackexchange.com/questions/14915/does-...
  - Qem 10mo ago
    Thank you. I thought that was settled matter.
andsoitis 10mo ago
> Our protection from cosmic radiation is mostly due to Earth's thick atmosphere, not its magnetic field Primary defense against cosmic radiation: magnetic field Secondary defense: atmosphere https://science.nasa.gov/science-research/earth-science/earths-magnetosphere-protecting-our-planet-from-harmful-space-energy/ https://science.nasa.gov/science-research/earth-science/eart...
- pfdietz 10mo ago
  Yeah, that's nonsense. The radiation in low Earth orbit is only a bit less than above the magnetosphere, and most of that difference is from shadowing by the Earth itself. In contrast, there's a massive decrease in radiation from LEO to to sea level. Radiation at ISS: 144 mSv per year Radiation on a trip to Mars: ~340 mSv per year Cosmic radiation at sea level: about 0.4 mSv per year The atmosphere is doing the heavy lifting in shielding us from cosmic radiation, not the magnetosphere.
  - magicalhippo 10mo ago
    > Radiation at ISS: 144 mSv per year > Radiation on a trip to Mars: ~340 mSv per year This seems to track with research that during a geomagnetic excursion[1], where the field strength dropped to about 10%, the cosmic radiation seems to have roughly doubled[2]. [1]: https://en.wikipedia.org/wiki/Geomagnetic_excursion https://en.wikipedia.org/wiki/Geomagnetic_excursion [2]: https://www.eurekalert.org/news-releases/1041098 https://www.eurekalert.org/news-releases/1041098
    - pfdietz 10mo ago
      To steelman the argument, perhaps what the magnetosphere is doing is stopping the atmosphere from making too much carbon-14. In shielding the surface from energetic cosmic rays, neutrons are produced, and these transmute N-14 to C-14 by the (n,p) reaction.
  - andsoitis 10mo ago
    > Yeah, that's nonsense. Assuming you're right, why do you suppose so many publications get it wrong? Not only the NASA one I linked to but also Wikipedia for example: https://en.wikipedia.org/wiki/Cosmic_ray https://en.wikipedia.org/wiki/Cosmic_ray Or the European Space Agency: https://www.esa.int/Science_Exploration/Space_Science/Cluster/Cluster_s_20_years_of_studying_Earth_s_magnetosphere https://www.esa.int/Science_Exploration/Space_Science/Cluste... You will forgive me if I take their assessment more seriously than yours, but I'm open to correcting my understanding.

by pfdietz 10mo ago

nobodyandproud 10mo ago

I don’t see any problems with the quote.

nephihaha 10mo ago

The magnetic field deflects particles from the Solar Wind, whereas the atmosphere blocks a lot of the radiation as I understand it.

pfdietz 10mo ago
The solar wind != cosmic radiation.

deleted 10mo ago

[deleted]

Qem 10mo ago

Without magnetic fields, the solar wind strips away atmospheres, like what happened to Mars.

pfdietz 10mo ago
This is questionable. https://earthscience.stackexchange.com/questions/14915/does-the-magnetic-field-really-protect-earth-from-anything https://earthscience.stackexchange.com/questions/14915/does-...
- Qem 10mo ago
  Thank you. I thought that was settled matter.

andsoitis 10mo ago

> Our protection from cosmic radiation is mostly due to Earth's thick atmosphere, not its magnetic field Primary defense against cosmic radiation: magnetic field Secondary defense: atmosphere https://science.nasa.gov/science-research/earth-science/earths-magnetosphere-protecting-our-planet-from-harmful-space-energy/ https://science.nasa.gov/science-research/earth-science/eart...

pfdietz 10mo ago
Yeah, that's nonsense. The radiation in low Earth orbit is only a bit less than above the magnetosphere, and most of that difference is from shadowing by the Earth itself. In contrast, there's a massive decrease in radiation from LEO to to sea level. Radiation at ISS: 144 mSv per year Radiation on a trip to Mars: ~340 mSv per year Cosmic radiation at sea level: about 0.4 mSv per year The atmosphere is doing the heavy lifting in shielding us from cosmic radiation, not the magnetosphere.
- magicalhippo 10mo ago
  > Radiation at ISS: 144 mSv per year > Radiation on a trip to Mars: ~340 mSv per year This seems to track with research that during a geomagnetic excursion[1], where the field strength dropped to about 10%, the cosmic radiation seems to have roughly doubled[2]. [1]: https://en.wikipedia.org/wiki/Geomagnetic_excursion https://en.wikipedia.org/wiki/Geomagnetic_excursion [2]: https://www.eurekalert.org/news-releases/1041098 https://www.eurekalert.org/news-releases/1041098
  - pfdietz 10mo ago
    To steelman the argument, perhaps what the magnetosphere is doing is stopping the atmosphere from making too much carbon-14. In shielding the surface from energetic cosmic rays, neutrons are produced, and these transmute N-14 to C-14 by the (n,p) reaction.
- andsoitis 10mo ago
  > Yeah, that's nonsense. Assuming you're right, why do you suppose so many publications get it wrong? Not only the NASA one I linked to but also Wikipedia for example: https://en.wikipedia.org/wiki/Cosmic_ray https://en.wikipedia.org/wiki/Cosmic_ray Or the European Space Agency: https://www.esa.int/Science_Exploration/Space_Science/Cluster/Cluster_s_20_years_of_studying_Earth_s_magnetosphere https://www.esa.int/Science_Exploration/Space_Science/Cluste... You will forgive me if I take their assessment more seriously than yours, but I'm open to correcting my understanding.